To activate hydrotreating and hydrocracking catalysts, refineries use sulfiding agents — specialized sulfur compounds that convert metal oxides (like CoMo or NiMo) into their active sulfide forms.
The most widely used sulfiding agents today are:
| Sulfiding Agent | Chemical Name | Sulfur Content | Common Alias | Key Advantages |
|---|
| DMDS | Dimethyl Disulfide | 68% | — | High sulfur content, cost-effective, stable decomposition profile |
| TBPS | Tertiary Butyl Polysulfide | 54% | Also known as DTBPS (Di-tert-Butyl Polysulfide) | Lower decomposition temperature, suitable when “methane make” is an issue |
| DTBPS | Di-tert-Butyl Polysulfide | 56% | Also known as TBPS or Tertiary Butyl Polysulfide | High-purity grade, safer handling, stable sulfur release |
Note:
In refinery practice, TBPS and DTBPS are often used interchangeably. DTBPS (Di-tert-Butyl Polysulfide) is a high-purity variant of TBPS, offering greater thermal stability and a smoother sulfiding profile.
Why Refineries Choose These Agents
- DMDS is preferred globally due to its higher sulfur concentration and cost efficiency.
- DTBPS (or TBPS) is selected where lower sulfiding temperatures or improved safety and odor control are priorities.
Both are crucial in ensuring complete and controlled activation of hydrotreating catalysts — a key step for producing ultra-low sulfur fuels.